1. Field of the Invention
The present invention relates generally to de-oxidizers and, more particularly, to a method and an apparatus for forming strip-formed continuous parcels for accommodating oxygen absorbers which make it possible to supply de-oxidizers in a form which can be handled without severe limitations on working time. In the present specification and the drawings attached thereto, the term "strip-formed continuous parcels" means a parcel structure in which a plurality of parcels each of which accommodates an oxygen-absorber compound are arranged one after another in the form of a strip.
2. Description of the Related Art
In the field of the art of preserving foods, preserving arts employing de-oxidizers are known, and the range of applications of such a preserving art has been widening from the preservation of various foods to that of medicines and, in addition, mechanical parts or the like.
The de-oxidizer is a product of the type in which a compound for absorbing oxygen (an oxygen absorber) is commonly charged into a small air-permeable parcel. The de-oxidizer together with objects to be preserved such as foods, machines, mechanical parts or the like (hereinafter referred to simply as "object") is hermetically enclosed within a packaging container to remove the oxygen in the container by absorption, thereby maintaining the quality of the object. The preserving art employing such a de-oxidizer is wide-spread among food manufacturers or the like in that the quality of products can be held for a long time merely by performing the simple operation of simultaneously enclosing de-oxidizers and products with packaging containers.
However, serious problems arise while de-oxidizer and objects are being enclosed within packaging containers. In general, de-oxidizers are marketed in a form in which a multiplicity of de-oxidizers, normally several tens to several hundreds, are packed in one outer parcel made of a material (for example, polyvinylidene chloride-coated nylon) of the kind through which oxygen does not easily permeate. As is well known, immediately after the outer parcel has been opened, the de-oxidizers start to absorb oxygen. Accordingly, once the outer parcel is opened, the de-oxidizers together with objects must be enclosed with packaging containers within an extremely limited time. If de-oxidizers which have been exposed to the air for an unduly long time are enclosed within packaging containers together within objects, the de-oxidizers can no longer completely absorb the oxygen in the containers. It becomes impossible, therefore, to maintain the quality of the objects over the requisite time period. This drawback may lead to various problems such as an increase in the number of returned goods, the occurrence of food poisoning and the like. Accordingly, food manufacturers must pay close attention to control of the time period required to handle de-oxidizers. In particular, in a system in which strip-formed continuous de-oxidizer parcels are automatically cut by an automatic charging apparatus to automatically package the individual de-oxidizer parcels together with objects, the more the number of successive parcels in each strip, the greater the merit of the automation. However, the number of successive parcels per strip is limited to a certain extent due to limitations imposed on the time period required to handle the de-oxidizers.
In addition, even if de-oxidizers are left in the atmosphere for a while after the outer parcel has been opened, the de-oxidizers must be able to retain their function sufficient to preserve objects. Accordingly, de-oxidizer manufacturers must produce de-oxidizers provided with a somewhat excessive oxygen-absorbing capability, with the result that the manufacturers must charge a greater amount of oxygen absorber than would otherwise be unnecessary. This problem leads to not only an increase in manufacturing costs but also an increase in the size of each de-oxidizer. The increase in size will impose inconvenient limitations on the form of a package used for enclosing a de-oxidizer and an object. The above-described problems become more serious, particularly when de-oxidizers having larger oxygen absorbing rates are employed. Accordingly, although it has been known that the oxygen in packages must be removed as rapidly as possible from the standpoint of preservation of foods, in the current situation the greater the oxygen absorbing rates of de-oxidizers, the more difficult the manufacture thereof.
Various proposals have been made in order to solve the above-described disadvantages which may be experienced during handling of de-oxidizers:
A) A de-oxidizer is known which is designed so that it does not start to absorb oxygen before it absorbs the moisture of an object after they have been packaged.
However, this known type of de-oxidizer has a number of problems:
1) If the de-oxidizer is not combined with an object of the type which contains a relatively large amount of moisture and which has a moisture activity of 0.7 or more, the moisture, hence oxygen, is not easily absorbed by the de-oxidizer. As a result, the kind of object to which the de-oxidizer is applicable is limited.
2) Even in the case of an object of the type which satisfies the conditions described in Paragraph 1), there are some cases where the moisture, hence oxygen, is not easily absorbed by the de-oxidizer, if the object is enclosed within a packaging container at an inappropriate position or in an inappropriate form.
3) The oxygen absorbing rate of the de-oxidizer does not rise until the de-oxidizer absorbs a sufficient amount of moisture. Accordingly, such a de-oxidizer is unsuitable for use in removing oxygen in a short time.
B) As another proposed method, it is considered that individual de-oxidizers are wrapped with parcels of material which do not easily allow permeation of oxygen, each de-oxidizer being taken out of the parcel immediately before it is packaged together with an object.
This proposed method is also undesirable for the following reasons:
1) The manufacturing costs of de-oxidizers increase to such an extent that the method cannot be utilized in practice.
2) Handling problems similar to those described above occur in the process, from the manufacturing of the de-oxidizers to the packaging thereof.
3) It is impossible to provide strip-formed continuous de-oxidizer parcels of the type which can be easily packaged together with objects in an automatic packaging apparatus.
Accordingly, the problem of limitations being imposed on the time period required to handle de-oxidizers still remains to be solved from the viewpoints of manufacturing processes, sales, usage and so on, and this problem is more serious for de-oxidizers having larger oxygen-absorbing rates.